No bit of nostalgia is sacred on ABC Family's "Pretty Little Liars." First, we were ruined for porcelain playthings forever after repeated visits to the creepiest little doll hospital on television, and now, we'll never be able to hum that cute little ditty "Teddy Bear's Picnic" ever again.

The network has released a tiny teaser from the series' upcoming Halloween episode, centering around Mona (a.k.a. A) messily painting a Joker-like grimace onto a mask, all the while singing about stuffed animals and ominously dripping scarlet paint onto her shoes. (What would the nurses at Radley say?)

The episode, titled "This Is a Dark Ride," takes place largely on a train and will feature a guest appearance by former "American Idol" contestant Adam Lambert.